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documentatie despre Amplificatoarele audio
Last Updated: Dec 09 2018 01:01, Started by
cataramaru
, May 27 2008 14:20
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0
#1
Posted 27 May 2008 - 14:20
Am de facut o lucrare de licentza si nu ma prea pricep.. rog dc sunt specialisti pe aicea in ale electrici sa atasheze cateva lincuri utile cu documentatia necesara pt amplificatoare audio si crector de ton !! Necesit 60 de pagini si nu stiu cum sa le scot !! Multzumesc
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#2
Posted 27 May 2008 - 15:09
cataramaru, on May 27 2008, 08:20, said: Am de facut o lucrare de licentza si nu ma prea pricep.. rog dc sunt specialisti pe aicea in ale electrici sa atasheze cateva lincuri utile cu documentatia necesara pt amplificatoare audio si crector de ton !! Necesit 60 de pagini si nu stiu cum sa le scot !! Multzumesc Daca necesitezi 60 de pagini si ai numai 2 scrise, incluzind prima pagina din Softpedia, incearca sa le tragi la Xerox: le bagi pe-o parte si le scoti pe alta. Aicisa daca am vrea sa-ti dam 60 de pagini s-ar necesita cel putin doi specialisti: unul in amplificatoare si unul in corector de ton. Am eu o lucrare , dar de 62 de pagini ,daca tu crezi ca te-ar putea ajuta la necesitate lasa-mi mesaj pe privat, impreuna cu-n cantec la moda, in interpretarea si la alegerea ta: Ajutati-ma si pe mine cu un ban, muzica Metrorex, versurile cu rima desperecheata sau Mamelor din lumea-ntreaga, muzica si versuri RATB, autobaza Filaret. |
#3
Posted 27 May 2008 - 18:36
nu am cerut proiect gata facut !! pur si simplu am cerut niste lincuri pe care sa le studiez .. si scuza'ma dc team ofensat cu problemele mele ! Ms mult o sa ma descurc si singur !!
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#4
Posted 27 May 2008 - 19:43
Cateva idei aplicabile si in cazul de fata gasesti aici:
http://forum.softped...=amplificatoare Pentru a ajunge la o norma de 60 de pagini, unele pagini din proiect pot contine scheme, altele imagini cu diverse produse... :D |
#5
Posted 27 May 2008 - 20:50
Daca chiar vrei sa aprofundezi fenomenul si nu doar sa compilezi referate iti recomand o carte poate usor depasita (necesita completari la partea moderna audio - vezi mosfeturi noi si integrate, precum si clasa D), dar pe care o consider si acum interesanta. Tot de pe forum am ajuns sa aflu de existenta ei si am gasit-o in talcioc la un mosulica - miroase si acum a tigari - imi imaginez ce e in camera lui... Partea practica e cam subtire, dar teoria e destul de buna. Poti sa completezi cu ce gasesti pe net la capitolul scheme.
Ar trebui sa o gasesti la biblioteci - poate e si de vanzare pe net pe undeva: L. Festila, E. Simion, C. Miron - Amplificatoare audio si sisteme muzicale Editura Dacia, Cluj Napoca, 1990 Cine cunoaste alte lucrari mai bune e binevenit sa ma completeze, as fi chiar bucuros - si eu vreau sa stiu mai multe despre tot ce tine de audio. |
#6
Posted 28 May 2008 - 08:01
Cateva materiale despre amplificatoare:
Quote Classes of Amplifiers Amplifiers do not actually increase the strength of an electronic signal. What happens instead, the signal is copied and enlarged. There are different schemes for amplifying the signal. There are different classes of amplifiers. These classes are A, AB, and C. There have been some special classes such as G, created by Hatachi. Class H created by Soundcraftsman. Class D for the so-called digital amps and Class T for Tripath's digital amplifiers. Class A amplifiers use one or more transistors that conduct during both the positive and negative cycles of the signal. This Class of amplifier has the lowest distortion but it is very inefficient and generates a lot of heat. A Class A amplifier requires that the amplifier generate the full current no matter what the output is. If you were simply listening to FM or watching a movie, the amplifier would be consuming as much power as if you had it turned up to full volume. In order to increase efficiency, Class B amplifiers use one transistor to conduct the positive portion of the waveform and another transistor to conduct the negative portion of the waveform. 99% of all audio amplifiers today are Class B. Class B amplifier can be built today so that its distortions are well below what the human ear can detect and nearly to the point where it is unmeasurable. Many amplifiers call themselves Class A/B. In reality, very few are. Early Class B amplifiers had a problem known as switching delay. In a class B design, a transistor works 50% of the cycle while another transistor works 50% of the cycle. In early class B amplifiers, there was a distortion created between the time the devices were switching back and forth. Some people referred to this distortion as notch distortion because there was a notch appearance on an oscilloscope between the two waveforms. Class A/B was created to leave the transistor conducting while the second transistor was conducting. This created an overlap between the two signals. The problem with this approach is that it created its own distortion called gumming. This means that the signal would get a little fatter where the two devices were both conduction. Today, if you look at a properly designed Class B amplifier on a scope, you will see no switching distortion. Class D amps are sometimes called digital amplifiers. There is really no such thing today as a digital amplifier. A Class D amplifier uses transistors that are either switched on or off to represent positive or negative values. The transistors are either on or off. The advantage of such a system is that it is highly efficient and generates very little heat. The disadvantage is that there can be a distortion caused between the switching of the positive and negative transistors as the positive and negative transistors can not be on at the same time. Many Class D amplifiers are finding their way into Subwoofers. They are inexpensive to build and the logic is that the switching distortion is not important in a subwoofer. Class T amps are a more refined switching amplifier developed by Tripath. It uses signal processing to eliminate the switching distortion of Class D. nOrh is currently working with parts from Tripath to determine the sonic merits using the Tripath parts. Our current view is that advantage to using Class T and Class D amps is not to achieve better sound than can currently be achieved with standard A or A/B amplifiers. Rather it is an attempt to create a lower priced amplifier that offers good performance. It is important to remember that classes of amplifiers do not describe quality but rather topology. http://www.bcae1.com/ampclass.htm http://sound.westhost.com/class-a.htm classA.doc 1.8MB 32 downloads classB.doc 666.5K 18 downloads efficiency.doc 790.5K 12 downloads ClassABAmplif.pdf 388.46K 28 downloads ClassD2.pdf 281.78K 24 downloads http://www.irf.com/t...tes/an-1071.pdf http://legwww.epfl.c...S...p by IR.pdf |
#7
Posted 03 September 2010 - 10:19
Ma poate ajuta cineva cu niste scheme de principiu, caracteristici de baza si clase de functionare ale amplificatoarelor de audiofrecventa?va multumesc
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#8
Posted 06 September 2010 - 17:16
http://www.circuitee...-amplificatoare
http://www.netxpert....o...0&Itemid=32 http://www.netxpert....o...4&Itemid=32 http://www.scritube....ice72912623.php si engleza: http://en.wikipedia....plifier_classes http://www.tpub.com/...s/book7/25e.htm si putina teorie: http://www.etc.ugal....u/CEF-curs5.pdf B/AB: http://www.google.ro...xqH3PF-4VpUb58A Clasa D: http://en.wikipedia....ching_amplifier s.a.m.d. |
#9
Posted 06 September 2010 - 17:24
Ca daca face singur un simplu search si pe forum, gaseste o multime de link-uri utile, dar e greu...
http://forum.softped...=amplificatoare http://forum.softped...=amplificatoare http://forum.softped...=amplificatoare inclusiv aici pe acest topic... B) |
#10
Posted 08 December 2018 - 23:07
Cu parere de rau trebuie sa va spun ca acum in 2018 inca nu se gaseste pe net stabilirea punctului de bias in dc si a liniei de incarcare in ac pentru cei 2 tranzistori in clasa b , sau ab.
Ar fi nevoie de o pagina si cateva formule dar nu este si gata . DACA cine stie si poate il rog sa puna ceva de genul , dar pentru cei care nu stiu nu are rost sa trimita linkuri sau altceva ca nu ajuta pe nimeni Multumiri pentru cine participa pozitiv . Edited by strainul1964, 08 December 2018 - 23:08. |
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#11
Posted 09 December 2018 - 00:20
strainul1964, on 08 decembrie 2018 - 23:07, said:
Cu parere de rau trebuie sa va spun ca acum in 2018 inca nu se gaseste pe net stabilirea punctului de bias in dc si a liniei de incarcare in ac pentru cei 2 tranzistori in clasa b , sau ab. Ar fi nevoie de o pagina si cateva formule dar nu este si gata . Iete un exemplu: Selection_001.png 431.75K 13 downloads Selection_002.png 348.18K 13 downloads Acu' că oi fi tu vreun geniu care reușeste sa calculeze valori ideale indiferent de dispersia parametrilor dispozitivelor semiconductore, deja discuția mă depășește. Da' io zic că nu ești, ci doar un habarnist care nu știe despre ce vorbește. Edited by mamaie112, 09 December 2018 - 00:20. |
#12
Posted 09 December 2018 - 01:01
Și, ca să revin, măcar reușești să înțelegi sensul frazei următoare?
"Determinarea punctelor statice de funcţionare la circuitele cu mai multe tranzistoare (rezolvarea circuitelor) se bazează pe scrierea ecuaţiilor lui Kirchhoff în nodurile şi pe ochiurile circuitului respectiv. Sistemul de ecuaţii care rezultă poate fi rezolvat cu ajutorul determinanţilor." |
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